Secret telegraphy system



F. CARTIER 1,868,967

S ECRET TELEGRAPHY SYSTEM July 26, 1932.

5 Sheets-Sheet 1 Filed March 30. 1927 TRANS/MIT 7'5? INVENTOR i FRANCOIS' CARTIER BY 5, 4 ,Qdm

A ORN EY July 26, 1932. F, CAR ER 1,868,967

SECRET TELEGRAPHY SYSTEM Filed March 30. 1927 3 Sheets-Sheet 3 R 2 1 V V i i i a 5 E g a- P i, -III INVENTOR FRANCOIS CARTIER BY x944 a/m A ORNEY Patented July 26, 1932 FRANQOIS CARTIER, OFPARIS, FRANCE PATENT OFFICE sncnn'r mnnneaarnv .sYsrEm Application filed March 30, 1927, Serial No. 179,440, and in'France April 23, 1926.

. The. present invention relates to a system of secret telegraphy and has as one of its objects to insure the secrecy of code telegrams transmitted and received by wire or wlreless by converting them into si als which can not be utilized by a crypto ogist for being re-converted into the original signals. The

transformation is effected at the time of transmission, while the inverse operation takes place on reception by means of a key strip, independently of the operator and 1n an automatic manner.

The following embodiment of the basic idea of theinvention is given by way of example and the same refers more particularly to the Baudot five-unit code system, though it will be understood that the invention applies toany other system of the kind of transmission and reception here concerned, with go or without wire. 1

The invention, both as to its construction and mode of operation togetherwith the objects and advantages thereof, will best be un- F derstood by reference to the following description taken in connection with the accompanying drawings, in which Fig. 1 is a schematic diagram showing the essentials of the Baudot system of telegraphic communication;

Figs. 2 and '3 are the transmitter and the receiver, respectively, embodying the novel features of my invention;

Figs. 4 and 5am detailed views of the keys used on keyboards U and N, respectively, 5 shown in Fig.2;

., Fig. 6 shows a practicable embodiment of portions shown in Fig. 2;. i Fig. 7 indicates the means for moving the ke} band or strip; o Fig. 8 is a diagrammatic illustration of a transmitter station; Fig. 9 shows the invention as applied to radiotelegraphio transmission: and

Fig. 10 shows the invention as applied to radio telegraphic rece tion.

The diagram in Fig. 1 illustrates the essential elements of a Baudot telegraphic communication system. D and D are similar distributors which are divided into segments d and (1 respectively, the number of which is always a multiple of five, one or two being added for synchronism. B and B are brushes which revolve synchronously by sliding, respectively, over se ents d, and d of distributors D and $5: in a way so as to be located always on segments of the same number. 0 is a ke board comprising 5 keys T furnished with two con tacts, one of which, the back contact, touches the bar P connected with the positive pole of a cell, while the other, the working contact,

makes contact with the bar P connected with the negative pole of a cell, the keys being respectively connected to the five consecutive segments 12-34.5 of the distributor D The five respeotive'segments l-2,3-.4-5 of the distributor D are connected with the five relays R R to R of the translator S which receives and prints automaticall the letters corresponding .to the groups. 0 five signals sent out by the keyboard C. There are provided as many keyboards and translators as there are groups of five segments in the distributors D and D In ordinary telegraphic communication work, the two brushes B and B areunited bythe line L, L. If the different keyboards or translators are located at different stations, there is provided at each station a distributor and a friction brush, while a general line is furnished for connecting all of the brushes.

Each keyboard sends out but one letter corresponding to. five signals per rotation of the distributor. The different brushes B and B pass succesively over the segments al and d, corresponding to the different keyboards or different translators. These arrangements are well known.

The application of the basic idea of the invention to the particular transmission system here dealt with is effected in the following manner; The sequence of 5 signals corresponding to the letters keyed at C is transformed into other sequences of five signals bearing no relationship to the former which are apt to be used by a cryptologist to remake the signals originally sent out.

(1) Transmission.-The transmitter device comprises essentially (see Fig. 2) two adj acentkeyboards U and N the keys K and 100 K of which rock between the two bars A; and A, which are united with the two poles of a cell; a group or bank of five electromagnets, the keepers of which are connected to the five consecutive segments of the distributor D and rock between the two bars P (idle) and P (when a current flows through the correspondin electroma-gnet) the bar P is connected wit the positive pole of a cell S, and the bar P, with the negative pole of a cell 5,; and a brush B which communicates with the line L and which turns uniformly while sliding over the segments of the distributor Di.

The keys of the keyboard Uhave the diaammatic form as indicated in Fig. 4. en idle, aspring R maintains contact between the key and the bar A while when doressed it brings pressure to bear upon the ar a The keys of the ke board N have a form as shown in Fig. 5. n insulatin strip a is placed upon the bar A, thus raising the end m and gressin the other end 1:. upon the bar A T e sai insulating strip is provided with holes. When one of the latter happens to be underneath the end m, the key K rocks under the action of the spring R and comes to touch bar A,, while the other end n-ceases to make contact with the bar A The holes of the insulating strip are separated by intervals or spaces equal to those of the keys K of keyboard N in Fig. 2. They form series of 5 intervals comprising holes of variable number corresponding to the signals or signs or the Baudot five-unit code.

Fi 2 corresponds to the case where the letter is manipulated upon the keyboard U and where the holesof the insulating strip a corres 0nd to the letter N. The diagram shows hat in this case, only the second, fourth and fifth of the series of 5 electromagnets J are passed by currents and these cause their keepers to be pressed upon the contacts P Brush 13 by wiping over the corresponding segments or the distributor I) will produce on the line L a sequence of impulses corresponding to the letter J. Hence, the letter actually sent out difiers from the one keyed at U ut it depends upon the letter correspon ing to the holes of the insulated strip a, vgiich in the present instant was for letter e Itevery time a letter is keyed at U, the strip is shiited in a way so as to bring anew series or holes under the keys K; or keyboard N, the open letter that is manipulated will set us in the line L series of im ulses corresponing to the code letters, tee displace ment oi which with relation to the open-langua letter'varies constantly.

ence, the work or coding is eiiected automatically with an tnooherenfi keyas long as there are spaces between the holes on the insulated strip, which may be called the key band or strip.

The forward travel or the latter is eflected automatically upon each rotation of the brush B by means of a special electroma net E which is actuated every time the brus passes over a segment of the distributor involved in such forward feed.

Fig. 6 represents a practicable disposition of the electromagnets J of the transmitter with their armatures or keepers F connected to distributor D, and contacts P and P,

Fig. 7 shows in what way the forward movement of the key band or strip may be controlled by a pawl and ratchet device P. a

is the key band rolled over the supply drum .G, while E is the electromagnet controlling cluding the special segments. The brush B5 turns in synchronism with the one of the transmitter so that they both pass at the same time over corresponding segments. The group of five electromagnets J 9 controls five keys which come to make contact with A, whenever a current flows through the corresponding electrcmagnet, and with A, when there. is no current flowing. The bank N, is analogous to bank N of the transmitter. The same is actuated by a key band identical to the one used insendin The bank U, istthe group of relays of't e ,Baudot transa or. s

The circuit connections are established in the manner shown in Fi 8. It will be seen that if the series of im u see received over the line L, the brush 13,, t e segments of the distributor D, and the five electromagnets J,

corresponding to the letter J, and if at the letter N which has served as a key letter in my example, the relays U. will produce in 0 on language the letter U which is the one t at had been keyed.

The forward movement or the k strip is produced at the receiving end-exact y in the same way as during sendin An electromagnet E, corresponding to i at the transmitting end is similarly connected to a special segment Set: the distributor and controls a pawl and ratchet device diagrammatically shown in Fig. 7.

The safety or the cryptographic or secret system described above depends upon the same time to contacts 7N, correspond to the r e length of the key strip which is the only secret element of the system. This secrecy will be practically absolute as long as the number of letters of the assembly of coded text does not exceed from 4 to 5 times the number of intervals of the key strip.

Key interrupt-ions may be produced by modifying at the beginning of each message or series of messages the position of the key strip, and there are as many variations or modifications of this nature as there are spaces or intervals in the key band.

It will be evident that there are a great 7 number of possible modifications. Moreover,

inbefore described.

If in Fig. 2 the line is doneaway with and if the brush B is joined with the positive pole of the cell S by way of an electromagnet M (shown in Fig. 9) the system is useful for and applicable to radiotelegraphic transmission. The electroniagnet M, according to whether it attracts its keeper or not, will cause the sending out of impulses or spaces, that is. either working or idle waves.

The same thing holds true for reception; the working signals received by the antenna may cause the closing of the circuit of a local cell in the relay J (Fig. 10) the receiving system being conveniently disposed for this object, the particular solution and means to be adopted, of course. difiering according to the system of radiotelegraphy that is used.

. Accidental jamming, interference, and at- .mospherics are able only to occasion local errors without exercising any influence upon the sequence of messages.

Having thus particularly described my invention, I claim:

1. In a system of telegraphic communication, a key board comprising a series of manually operated keys, a second key board having a series of automatically operated keys, a cipher strip for operating said second keys, a series of electromagnets connected in series relation with corresponding keys in each of said key series, a transmitting distributor having a series of collected segments. the keepers or armatures of said electromagnets 5 being connected to a segment of each dis- 7 tributor, and a rotatively mounted brush connected to a line circuit for sweeping over the segments for transmitting electrical impulses resulting from the conjoint action of manual 35 and automatic keys on the electromagnets,

and additional means associated with said brush and segments for advancing said strip one step at the end of each revolution of said brush.

2. In a system of telegraphic communication, a key board comprising a series of manually operated keys for composing desired signals, a second key board having a series of keys automatically operated by means of a perforated key strip,a series of electromagnets, each of said electromagnets connected in series relation with corresponding keys in each of said key series, the relative positions of corresponding keys determining the energization or de-cnergization of the electromagnet associated therewith, a transmitting distribnter having a series of collecting segments, the keepers or armatures of said electromagnets each being connected to a seg ment of said distributor. a rotatively mounted brush contact connected to a line circuit for sweeping over the series of segments whereby electrical impulses, dill'ering from the original manually-keyed signals, are transmitted, and means electrically associated with said segments and brush for advancing said strip one step at the end of each revolution of said brush.

3. In a system of telegraphic communication, a key board comprisinga series of manually operated keys for composing desired signals, a second key board having a series of keys automatically operated by means of a strip, a series of electromagnets, each of which is connected in series relation with corresponding keys in each of said key series, the relative positions of corresponding keys determining the energization of the electromagnets associated therewith, a transmitting dist-ributer having a series of collecting seg ments, each being electrically connected to a corresponding keeper of said electromagnets, a brush contact connected to a line circuit for sweeping over the series of segments whereby electrical impulses, differing from the original manually-keyed signal, are transmitted, a distributer at the receiving station similar to said first mentioned distributer, a rotatively mounted brush contact associated therewith connected to the line circuit and moving in synchronism with the brush at the transmitter a series of relays associated with the distributer and energized by the transmitted electrical impulses, and means cooperating with said relays for reconverting said impulses with those originally keyed, and means electrically associated with said transmitting segments and brush for advancing said strip one step at the end of each revolution of said brush.

FRANCOIS CARTIER. 

